Air-compressor



(No Model.) 2 Sheets-Sheet 1.

U. CUMMINGS.

AIR COMPRESSOR. No. 363,609. Patented May 24, 1887.

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N. PETERS, Phutu-Ligho n hgr, Washington. I10v (No-Model.) 2 Sheets-Sheet 2.

U. OUMMINGSV AIR COMPRESSOR.

No. 363,509. Patented May 24, 1887.

N. PETERS. PnoXo-Lilhngrzpher, Wnhin wn, n. c,

UNIT D STATES PATENT OFFICE.

URIAHCUMMINGS, OF BUFFALO, NElV YORK.

AIR-COMPRESSOR.

SPECIFICATION forming part of Letters Patent No. 363.509, dated May 24, 1887.

Application tiled Octohcrilfi, 1886. Serial No. 217,274. (No model.)

To all whom it may concern:

Be it known thatI, URIAH CUMMINGS, of the city of Buffalo, in the county of Erie and State of New York, have invented a new and useful Improvement in Air-Compressors, of which the following is a specification.

This invention relates to that class of aircompressors in which the air is compressed by a reciprocating piston moving in a cylinder, and which are adapted to compress the air to a high pressure-for instance, as a motor in rock-drills and other machines.

The object of my invention is to produce an air-compressor of this character which can be operated at a high rate of speed, and which is durable and easily kept in order.

In the air-compressors now most generally,

used the heat which is liberated by compressing the air is removed by injecting water into the compressing-cylinder; but this is objectionable, because the water often carries solid impurities with it, which injurethe contactsurfaces of the cylinder and piston to such an extent as to render the renewal of these parts necessary. V

My'invention is designed to overcome this difficulty; and the invention consists of the improvements which will be hereinafter fully described, and pointed out in the claims.

In the accompanying drawings, consisting of two sheets, Figure 1 is a side elevation of my improved air-compressor. Fig. 2 is a top plan view of the same. Fig. 3 is a top plan view of the steam and air pipes. Fig. 4. is a longitudinal section of the cylinder and connecting parts on an enlarged scale. Fig. 5 is a sectional view of the air-escape valve on an enlarged scale. Fig. 6 is a similar view of the air-inlet valve on an enlarged scale.

Like letters of reference refer to like part in the several figures.

A represents the horizontal bed of the aireompressor, and A A two horizontal cylinders secured to the same and provided, re spectively, with pistons a a, which are secured to the ends of a piston-rod, a Each cylinder is closed at its inner end by a head, I), which is provided with a stuffing-box, b, through which the piston-rod works.

0 0 represent the stcam-va1ves arranged, re-

spectively, in valve-chests c c, the inner ends of which are connected with the cylinder by ports d at, through which the steam passes to and from the inner ends of the cylinders.

E represents the steam-supply pipe provided with two branch pipes, e e, which connect with the valve-chests c c and conduct the steam to the same. 7

f f represent the exhaust-ports formed, respectively, in the cylinders A A and connected with an exhaust-pipe, F, by branch pipes F F As shown in the drawings, the steam-valves O G are constructed in the form of rock-valves and provided 011 the outer sides of the "alvechests with arms 9 g, which are connected by a rod, 9 so that both valves move in unison. Valves of any other suitable construction may, however, be employed, if preferred.

H represents a cross-head secured to the piston-rod (6 between the cylinders AA, and h represents the horizontal guide-bars on which the crosshead slides, and which are supported on the bed A.

I represents a horizontal shaft provided with fly-wheels I, and j ournaled in bearings-i,foi'nied on the bed A in rear of the cylinder A J represents rods which connect the crosshead H with cranks j, secured to the fly-wheel shaft I, and whereby said shaft is rotated.

K represents an eccentric secured to the flywheel shaft I, and connected with the valve arm 9 by a rod, is, so as to actuate the valves. The latter are so arranged with reference to their respective steam and exhaust ports that one valve admits steam to its cylinder when the other exhausts.

L L represent the air-inlet valves arranged V air enters, as represented in Fig. 6.

N N represent the air-escape valves, which may be of any suitable or well-known construction. These valves are also arranged in the outer heads of the cylinders and connected by branch pipes at with an air pipe, n, by which the compressed air is conducted to a suitable and finally forcing such air through the airescape valve N into the compressed-air conduit. The piston a in the cylinder A is at the same time moved toward the inner end of its cylinder, and the steam escapes from before the piston a through the exhaust port f, while the outer air enters the opposite end of the cylinder through the open air-inlet valve L.

. During the return stroke of the pistons the steam is exhausted from the cylinder A and air is admitted to the same, and steam is admitted to the cylinder A and the compressed air is expelled from the same. In this manner each cylinder operates alternately as a steam cylinder and as an air cylinder, and each cylinder is at every other stroke supplied with steam, whereby the inner surfaces of the cylinders and the pistons are at short intervals supplied with moisture,which insures the smooth running of the machine and prevents the parts from becoming overheated. By connecting the pistons and valves with a fly-wheel shaft, the machine can be operated at a high rate of speed. The steam valves may be so constructed that the steam is used with a proper degree of expansion.

The heat which is generated in each cylinder by compressing the air therein is transmitted to the steam which is admitted to the cylinders and evaporates thewater mixed with the steam, thereby raising the effective steampressure in the cylinders beyond the pressure in the steam-supply pipe and enabling the compressor to furnish compressed air for working purposes of equal or higherpressure than the steam by which the compressor is actuated' The useful effect of the steam is by this means considerably increased.

If desired, the piston-rod may be extended through the outer head of one of the cylinders, and the cross-head may be secured tothe outer end of the piston -rod, instead of being arranged between the cylinders, as shown. In this case the two cylinders can be arranged closely together, and a single steam-valve may be employed for controlling the flow of steam to and from both cylinders, instead of two sepa rate valves, as shown.

I claim as my invention 1. In a steam-actuated air-compressor, the combination, with two actuatingcylinders of equal diameters and two pistons'working in the same and connected by a piston-rod, of a valve mechanism whereby steam is alternately admitted to one end of each cylinder and exhausted therefrom, air inlet and escape valves, through which the air is alternately admitted to and emitted from the opposite end of each cylinder, and a fly-wheel and shaft rotated from said piston-rod and operating said valve mechanism, substantially as set forth.

2. In a steam-actuated air-compressor, the combination, .with two actuating-cylinders of equal diameters and two pistons working in the same and connected by a piston -rod, of separate steam-valves, one applied to each cylinder, whereby steam is alternately admitted to each cylinder and exhausted therefrom, air inlet and escape valves, through which air is alternately admitted to and emitted from the opposite end of each cylinder, and a fly-wheel and shaft connected with the piston-rod be tween the cylinders, substantially as set forth.

3. In a steam-actuated air-compressor, the combination, with two actuating and compressing cylinders and two connected pistons working in the same, of a valve mechanism whereby steam is alternately admitted to one end of each cylinderand exhausted therefrom, air-inlet valves through which external air is alternately admitted to each cylinder, air-escape valves through which the compressed air is alternately emitted from each cylinder at the same pressure, and a fly-wheel and shaft rotated from said pistons, substantial] y as set forth. 7

Witness my hand this 23d day of October, 1886.

U. CUMMINGS.

WVitnesses:

JNo. J. BONNER, CARL F. GEYER. 

